The comet-chasing Rosetta mission was at the top of the journal’s annual list of groundbreaking scientific achievements.

When a group of middle-schoolers from a small rural town in northern California started following a research curriculum called the Mars Student Imaging Project (MSIP), they had no idea that they could make a world-class scientific discovery. Instead of studying worksheets to learn science concepts, these students were conducting their own experiment using a camera orbiting Mars. They were active participants in exploration instead of just reading about it.